Various systems exist for providing assistance to drivers of motor vehicles. For example, one such area of assistance relates to automated road sign recognition.
Road sign recognition may be accomplished by using suitable devices (e.g., optical devices such as a camera) for perceiving or detecting the surroundings of a motor vehicle. Systems are available commercially, for example, both from automobile manufacturers, and from manufacturers of portable navigation devices (PNDs). The PND systems are based on GPS signals and map data for supplying the driver with information relating to road signs.
Some existing systems implement a camera device for improving recognition accuracy and robustness. The manufacturers of vehicles use front-mounted camera devices and means for combining signals with data relating to the driving state of the vehicle. A further option is means for combining signals with navigation devices.
In such systems certain issues exist such as, for example, how long to maintain display of a particular regulation value to the driver (i.e., how long is such a value relevant), what to do when multiple indicators are recognized in succession, and how should a vehicle change in direction or crossing of an intersection affect display of the regulation value.
US 2012/046855 discloses systems methods for recognizing road signs. An image of a road sign is captured by least one image sensor. A vehicle computer receives the image data representing one or more road signs along a route and displays one or more images of the road sign based on the image data. The display is capable of presenting one or more status of the road sign based on one or more travel states for the vehicle such as an amount of elapsed travel time, distance travelled, or speed.
EP 1 826 736 B1 discloses a vehicle having a controller for determining a road sign and/or regulation content of the road sign, where the road sign is covered in a camera picture. A display is provided for displaying a representation of the road sign or an information about the regulation content. The display is changeable between two output formats, which have smaller and higher probabilities of road sign determination, respectively. A monochrome or grey value representation takes place in one output format, and a colored representation takes place in another output format.
EP 1 131 803 B1 discloses a device and a method enabling traffic signs to be recognized and displayed to an observer in the form of a memory aid. The reject rate with respect to the recognition of objects that are recognized as traffic signs remains low. Image data from an image sensor is analyzed and classified in an information processing unit. Image sections and/or image data corresponding to a symbolic representation stored in a memory unit is/are archived in a memory unit and represented by means of a display unit on the basis of classification results. When the image data is further processed, the extracted objects are separated into specific classes and sub-classes of traffic-signs and classified. A synthetic image of a traffic sign is generated, stored in a memory unit and displayed by means of a display unit.
DE 296 10 677 U1 discloses a system for displaying road signs, the system having, in addition to a display for displaying messages to the driver, a signal transmitter which activates the display as a function of the distance traveled, and makes the display visible or invisible.
DE 198 29 162 A1 discloses the use of an electronic camera and of an image recognition device cooperating therewith, for the purpose of recognizing road signs, wherein the image recognition device can be reset to its starting state if, the vehicle turns off the road, for example after a road sign indicating a speed limit.